<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <div class="demo">1</div>
    <div class="demo">2</div>
    <div class="demo">3</div>

    <!-- <script src='./jquery.js'></script> -->
    <script src='./myjQuery.js'></script>
    <script>
        // 0 1 2 3
        // -1 -2 -3 
        // null undefined  [dom, dom, dom]
        // $('.demo').get()
        // $('.demo').get();


        // eq

        console.log( $('.demo').eq() );
        

    </script>
</body>
</html>